Having spent 16 previous volumes so wonderfully delineating his pair of 18th-century heroes, Captain Jack Aubrey and physician/secret agent Stephen Maturin, and the world in which they live, O'Brian apparently feels that series fans will be delighted to share any aspect of their lives. He's probably right. In this 17th seagoing adventure (after The Wine-Dark Sea), O'Brian successfully manages the trick of devoting much of the book to matters more domestic than naval. Stephen's words to Jack's wife, Sophie, hardly smell of gunpowder and brine: ""`...that was a sumptuous feast you gave us.... I returned to the venison pasty not once but three times.'"" Jack is greeted with an unexpected promotion to full Commodore when he arrives back in England. Meanwhile, Stephen finds that his wife, Diane, has run away because of her guilt over the apparent autism of their young daughter, whom Stephen meets for the first time, and with whom he is painfully unable to communicate. When next they head out to sea, both men depart under clouds: a jealousy-induced disagreement with Sophie weighs on Jack's mind, while plotting by Stephen's enemies has put his fortune and friends in jeopardy. Re-engaging in the Napoleonic Wars, the new Commodore takes his motley and often fractious squadron on a foray to disrupt slave traders in the Gulf of Guinea and then to the seas off Ireland to engage the French. As always, O'Brian tells his tale with great historical and nautical accuracy. Those who have sailed these seas before will happily go along on this latest voyage. (Apr.)